Nordic nRF52840-DK J-LINK cant connect

[eric20075]

I bought Nordic nRF52840-DK at an electronics store in Taiwan.
J-link cannot be detected when connecting to a computer.
I bought two pieces nRF52840-DK.
One of them can be used normally but the other one cannot be detected (such as the following video).
What should I do if this happens?

YouTube link:   https://www.youtube.com/watch?v=sXKMtRS-h0o

[tesc]

Hi,

I cannot see from the video the settings of the following switches:

SW8 (also marked "Power") in the bottom left corner of the board. Should be set to ON.

SW9 (also marked "nRF power source") slightly upwards between the USB connection and the interface MCU (PCA10050 sticker). Should be set to VDD.

SW6 (below marking "nRF ONLY | DEFAULT") at the very top of the board, close to the right side (antenna side). Should be set to DEFAULT.

Can you check that all three switches are set correctly?

Regards,
Terje

[eric20075]

I have the correct opening of all the things you said, but I can’t feel it. I think it should be the board.

[eric20075]

I have bought two identical development boards. The two operations are exactly the same, but one of them does not detect J-LINK. Is this a board?

[eric20075]

I am attaching a video: this problematic board LED1 is in the state of breathing light, and LED5 is not lit.

https://www.youtube.com/watch?v=dz2QD9WxL3s&feature=youtu.be